तस्मात्सर्वेषु कालेषु मामनुस्मर युध्य च। मय्यर्पितमनोबुद्धिर्मामेवैष्यस्यसंशयम् ॥

tasmāt sarveṣhu kāleṣhu mām anusmara yudhya cha mayyarpita-mano-buddhir mām evaiṣhyasyasanśhayam

Therefore at all times think upon Me only and fight. With mind and Reason set on Me, without doubt thou shalt come to Me.

In plain words: So Krishna tells Arjuna to remember him at all times and still do his duty and fight. If his mind and understanding stay fixed on Krishna, he will surely reach him.